Wafer coil manufacture



Dec. 5, 1961 Filed Nov. 8, 1955 F. H. WALKER ETAL WAFER COIL MANUFACTURE2 ysheets-sheet 1 Dec. .5, 19.61 F. H. WALKER Em. 3,011,374

WAFER COIL MANUFACTURE Filed Nov. 8, 1955 2 sheets-sheet 2 IN V EN TORJ'FA/VK H. WAL/(ER ALBER 7' ZAC/f BYW Mr ATTORNEY 3,011,374 WAFER COLMANUFACTURE Frank H. Walker, Salem, and Albert Zack, Danvers, Mass.,assignors, by mesne assignments, to Sylvania Electric Products Inc.,Wilmington, Del., a corporation of Delaware Filed Nov. 8, 1955, Ser. No.545,640 1 Claim. (Cl. 82-48) This invention relates to methods andapparatus for the manufacture of waferv coils, and particularly for themanufacture of such coils by cutting slices from a roll of metallic foilWound with insulation between its turns.

In making such coils, a wide sheet of metallic foil and a wide sheet ofinsulating material are generally Wound on a core. Several sheets offoil, or several sheets of insulating material, or several sheets ofeach, may be wound together. Instead of using a sheet of insulatingmaterial, an insulating coating may be placed directly on the foil, ifdesired, and the insulated foil then wound directly on itself. Butwhatever the method of winding the roll, the result will be a winding offoil, with solid insulating material between `the turns of the winding.The winding will generally be impregnated with a suitable insulatingmaterial such as wax or a plastic.

Thin wafer coils are then cut from the wide roll of Wound foil. Thecutting can be done with a knife if the roll is impregnated with asuiciently soft material such as wax, or with a rotating cutter wheel ifthe impregnating material is a hard resin'.

An object of the present invention is to facilitate the cutting of saidcoils from the roll. A further object is to provide automatic means forperforming the cutting.

When the cutting is done by a rotating wheel, the material in the coilis sawed out and lost for a distance equal to the thickness of thewheel. Since the thickness of the coil to be cut is in many cases verysmall, the thickness of the material cut out between coils by the wheelcan be a considerable portion of the thickness of` the coil. 'Iherecould thus be a large loss of material, unless the wheel is extremelythin compared to the thickness of the Wafer coil to be cut from theroll. Making the Wheel thin reduces its heat conductivity, but we ndthat excessive heating can be prevented by using a cooling fluid, forexample, water, on the wheel and the coil.

When a knife is used, there is no material lost in the cutting. 'I'heknife blade must be extremely thin, however, and we lind that tomaintain its shape during the cut, the blade should be very rigidly heldso that it cannot bend. In general, this can be achieved by fixing theblade between two rigid support members, each of which is secured to theblade along a non-cutting edge thereof. In the embodiment described, theblade is held at the apex of a comparatively'heavy V-shaped or U-sh'apedmember, the legs of which spread out sufficiently to clear the coil.

According to our invention, the wound roll is rotated While the cutteris r'eciprocated transversely against the coil, the cutter being movedalong the axis of the roll betweencuts a distance about equal to thedesired thickness of the wafer coil. vWe lind that the speed with whichn Ythe cutter is moved in cutting the coil is quite important,

too high a speed ripping the layers of foil and paper, and y too lowaspeed smearing vthe foil over the face of the coil. A speed such that'the cuttenmoves into the roll during each revolutionthereof a distanceabout equal to the distance between turns of the foil is preferable, andthe speedshould not ordinarily` be more than about twice that speed norless than about half of it. i Y.

Since the speed is important, it should also bel uniform while thecutter is in contact with the roll.l The cutter will corne to zero speedat.' each end ofthe path in which 3,011,374 Patented Dec. 5, 1961 theroll is cut through, after which the cutter can drop to zero Vspeed andreverse.

In the embodiment hereinl described, a hydraulic check Y valve is usedto keep the motion of the cutter uniform as it passes through the roll.Y

After the cutter has cut a wafer coil from the roll and has thenwithdrawn to its starting position, the cutter is moved in the directionof the longitudinal axis of the roll a distance equal to the desiredthickness of the coil to be cut off, proper allowance being made for thethickness o f the cutter. This motion can be achieved 'by turning athreaded rod which passes through a correspondingly threaded portion inthe cutter support, the rod being set in a direction parallel to thelongitudinal axis of the roll. The end of the rod is xed to a piniongear which is turned by a reciprocating rack. The pinion is xed to therod by a slip-clutch, so that the pinion will turn the rod during theforward motion ofthe rack, but not during 30 the rack is placed above orbelow the pinion.

We iind the proper control of the various movements described above tobe quite important.

In the embodiment described, the cutter is reciprocated by a pistonoperating in a cylinder with air inlets at each end. When the cutter isat each end of its stroke, it actuates mechanism which shifts the airinput to the proper inlet to move the piston in the reverse direction.At the return end of its stroke, the cutter actuates mechanism whichmoves the cutter longitudinally by the amount of the desired thicknessof coil to be cut, and the ending of that movement actuates mechanismwhich starts the cutter on its cutting stroke. After the cutter hasmoved a longitudinal distance corresponding to the cutting of apredetermined number of coils, it engages a switch which shuts 0E allfurther motion of 'the cutter.

The cutter itself need not actuate the various mechanisms describedabove; the mechanism can be actuated by the cutter support or byanything which moves with the cutter.

Although the preferred embodiment described below uses resilientswitches, air cylinders and solenoid-operated air valves to control themotion of the cutter, other devices canbe used.

A particular embodiment of the invention is 'described in detail belowand shown in the drawings, in which:

FlGURE 1 isa plan View of apparatus embodying the invention;

FIGURE 2 is Y'a side elevation of the air cylinder land -check valveused in the apparatus;

Y invention; and

FIGURE 5 is a front view of the samecutter. `FIGURE 6 is a View ofanother cutter. 4In FGURE 1, the'V foundation for the device is astandard commercial lathebed 1, having the longitudinal ways 2, 3 alongwhich the lathe cross-feed carriage 4 f slidesl The chuck 5, withitsjaws, rotates on anv axis parallel to the axis ofthe Yways,-and thewound roll-7. of :foil and insulation isjheld in the chuckS by said jaws6. The' chuck is rotated` by the beltjf8; The rbelt 8,

driven from one of the pulleys 10, drives one of the pulleys 9 whichtransmits motion to the chuck 5. The pulley 1t) is driven from anelectric motor 11 through another belt 12 and pulleys 13, 14. The gearratios by which the pulley 9fdrives the chuck 5 can be changed in theusual manner by gear shift lever 15, and the pulley ratio by belt shiftlever 16.

The carriage 4 has the usual threaded portion in engagement with thescrew-threaded rod or lead-screw 17, so that turning of the latter willmove the carriage longitudinally along the ways 2. The carriage 4contains a way 18 raised therefrom, which engage a cross-slide 19 in asliding fit, so that said cross-slide can move backand-forthtransversely to the longitudinal axis of the chuck 5. The tool holder 2Gextends upwardly from the cross-slide 19, and holds the cutting tool.

Thus far, except for the roll 7, and the cutting tool 23, thedescription has been of an ordinary commercial lathe. In what follows,the additions made to the lathe, and which act in combination withcertain parts of the lathe to cut wafer coils from the roll aredescribed.

In an ordinary lathe, the cross-slide 19 is operated by hand, through acrank which turns a screw to which the slide is threaded. In ourinvention, however, the screw is removed, and an air cylinder 21 whichcan be of a regular commercial type, arranged to reciprocate thecross-slide 19 and connected thereto by the connecting rod 31. Ahydraulic check valve 22 is also connected to said connecting rod 31 tomake the motion of the slide uniform as the slide carries the cuttingtool 23 through the wound roll 7 to sever a wafer coil therefrom.

The air cylinder 21 has a double solenoid valve 25 at the end thereofopposite to that from which connecting rod 31 extends.

The double solenoid valve 25 can be of an ordinary commercial type, itsstructure being shown substantially in FIGURE 3. A piston 80 in the aircylinder is connected to a post 30 on the cross-slide 19, by theconnecting rod 31. The solenoids 26 and 27, one on each side of valve25, actuate the valve, through connecting links 28, 29, to direct airinto the cylinder 21 at one end thereof or the other, depending on thedirection in which the air cylinder is to move the cross-slide 19. 'Iheconnecting rod 31 carries an extending arm 32, held thereto by the nuts33. In line with the path in which said arm will be carried by movementof the piston, and at each end of said path, are the switches 34, 35,actuated by the depressing of push buttons 36, 37 respectively. Theswitches 34, 35 are fixed to brackets 3S, 39, attached to the cuttingplatform 4.

The solenoid valve 25 is supplied with compressed air through pipe 40,connected to the inlet 41 through the conduit 4Z and one arm on theT-connection 43. The other arm of the T, through pipe 44, supplies theinlet Z4 of another solenoid valve 45 through the elbow 46. The solenoidvalve 45 actuates the air cylinder 47, allowing air to enter at one sideor the other of a piston 94 therein to move a connecting rod 48,extending from said piston. The latter is not shown in FIGURE 1, sinceit is inside the air cylinder 47, but it is shown schematically inFIGURE 2. The rod 48 is connected at its end to the rack 49, movabletherewith. The connecting rod 48 and the rack 49 are joined by athreaded rod 5t), the position of the rack being adjustable by turningsaid threaded rod in an internally-threaded hole in the end of rack 49.The lock-nut 51 secures the rod 50 in position after adjustment.

The pinion 52 is in engagement with rack 49 and above the latter, beingrotatable by movement thereof. Said pinion is attached to the threadedlongitudinal rod 17, generally called a lead-screw, through the slipclutch v53 and the adjustablegear train 54, the latter controlling theangular speed ratio between pinion 2 and lead screw Y 17. Theslip-clutch can be of a suitable type, wellknown itlv the art, t0transmit power only in one direction of rotation. The levers 55, in thegear train box 56, shift the gears and change the ratio when moved.

The direction of air ow in air cylinder 47 and hence the direction ofmotion of the connecting rod 48 is controlled by the solenoid 57 andanother solenoid on the other side of valve 45, and not appearing inFIG- URE l, because said solenoid lies under the position of motor 11.The solenoids are connected to the valve 45 in the usual manner, by theconnecting links 58, 59.

The connecting rod 48 carries the laterally-extending arm 60, which atthe end of the retracting stroke of the connecting rod 48, depresses thepush-buttons 61, 62 in switches 63, 64 supported from the base plate 65by the bracket 66. The switches 63, 64 are so located that the arm 60will depress the push buttons at the end of its retracting stroke.

Switch 67 is attached to the bed plate 1 of the lathe by bracket 68,which holds the switch in position such that its actuating push-buton 69is depressed by the cutter platform 4, at the end of the latterslongitudinal motion along the ways 2 toward the chuck 5.

'I'he motor 11 is attached to the base plate 65 by a suitable bracket70, from which extends a U-shaped bracket 71, whose ends carry thebearings 72, 73, in which the shaft 74, carrying the pulleys 10, turns.

The air supply to valves 25, 45 is turned on and off by operation of thesolenoid valve 75. The electrical circuit to the apparatus is turned onand oi by switch 76.

In FIGURE 2, the connecting rod 31, projecting from air cylinder 21, isconnected to the connecting rod 77 extending from the hydraulic checkvalve 22, by the connecting arm 32 which is held to the respectiveconnecting rods by nuts 79, 79, 33, 33, screwed to threaded portions ofthe rods 31 and 77.

A bracket 13S is attached to the lathe carriage 4 by the screws 139,140. A small angle piece 141 connects the air cylinder 21 to the bracket138. The plate 38 extends upward from bracket 4, to which it isattached, the connecting rods 31 and 77 passing through holes in plate38, the holes being large enough to permit easy motion of saidconnecting rods therethrough. A small angle piece 142 attaches checkvalve 22 to plate 38.

The check valve 22 has the adjusting screen 146.

The electrical and mechanical circuit is shown schematically in FIGURE3. The solenoid valve 25 is at the end of air cylinder 21, in which themain piston 80 can reciprocate. The valve pistons 81 and `82 are xedtogether mechanically so that they move as a unit. Valve piston 81 isshown in closed position, cutting oft' air ow through the passage 8f3.Valve piston 82 is shown open, allowing air iiow through passage 84 toone side of the piston.

The main piston is shown at the end of its return stroke, with arm 32closing switch 35. The latter is in a series circuit with the solenoid57 and the secondary 85 of transformer 86, the primary 87 of saidtransformer being connected to a suitable power line through the doublepole switch 76. The solenoid 57 operates the valve piston 88, the latteropening the passage 89 to air ow when the solenoid 57 is energized. Theopposite valve piston 90 is fixed mechanically to valve piston 8S andmoves therewith, so that when one valve is open the other closes.

The valve piston 9th can be brought to open position, that is, aposition opening passage 91 to air ow, by the passage of current throughsolenoid 92, which actuates it. One end each of solenoid 57, solenoid92, and secondary '85 is shown connected to ground, which means that`there is a common connection joining one end of each of them. Theswitch 63 is in the series circuit connecting solenoid 92 to transformersecondary 85.

Switch y64 is in series with solenoid 27V and the power line, and switch34 is similarly in series With solenoid 26 and the power line, thatisthe power line which supplies the primary 87 of the transformer S6.Switch 67. at the .end of the longitudinal travel of cross slide 19, .isin FIGURE 2. Switch 76 is then closed, and since switch 35 is heldclosed by arm 32, the relay 57 will be energized, pulling aside thevalve piston 88 and allowing air to ow through passage '89 to one sideof air cylinder piston 94, thus driving it forward. For convenience,motion toward the top of the drawing in FIGS. 1 and 2 is considered asbeing in the forward direction.

Rack 49 moves with piston 94, turning pinion 52 and hence turninglead-screw 17 to move carriage 4 the distance of the desired thicknessfor the wafer to be cut. At the end of the forward stroke, arm 60 closesswitches 63 and 64. The closing of switch 63 actuates solenoid 92,thereby pulling valve pistou 90 `aside -to open the passage 91, allowingair to ow therethrough to the other side of piston 94 forcing itbackward. On the backward stroke the motion of this piston will move therack 49, which will rotate the pinion 52; but the rotation of saidpinion will not rotate the lead-screw 17, because slip-clutch 53 permitsmotion only in the other direction.

Meanwhile, the closing of switch 64 at the end of the forward stroke,actuates solenoid 27, which retracts valve piston y81, allowing air toow to the rear of piston 80, thereby driving the latter forward. Thecross-slide 19, being attached to the piston 80 by connecting rod 31,also moves forward. This is the cutting stroke, because the cross-slidecarries the cutting tool with it.

At the end of the cutting stroke, the arm 32 closes switch 34, therebyactuating solenoid 26V and opening the passage 84 allowing air to passtherethrough and force the piston back to its original position at theother end of its stroke. The switch 35 is then closed by arm 32, and theprocess repeats itself, cutting another wafer.

The cutting of wafers proceeds in the above-described manner, until nearthe end of the useful portion of roll '7, the cross-slide engages switch67, closing the same and thereby energizing solenoid 93, which actuatesvalve 75 and shuts olf the air supply, leaving the cross-slidestationary until the machine is restarted with another roll 7.

The cutting tool 23 of FIGURE 1 is shown. in more detail in FIGURES 4and 5. The thin knife blade 78, of the razor blade type, is clampediirrnly between the flat-sided U-shaped yolks 95, 96 by the screws97-100, inclusive. The open ends 101, 1020i the yolks 95, 96, extendslightly beyond the cutting edge 103 of the blade 78, shown just aheadofthe roll 7, which appears in phantom.

The blade is thus held lirrnly against bending, so that it will retainits shape when in contact with the roll. The middle of the yolk is heldfirmly to vthe metal post 104 by the screw 105 and the lock-washer 106.'The arm 107 extends from post 104 in a direction out of the paper, andis wider near post 104 than it is at its free end. The ann 107 passesthrough an opening in latter holder 20, and is held in the usual mannerby a screw whose square head is shown at 108.

In FIGURE 6, a thin rotating Wheel 110 is used asa cutter. The wheelisxed atv its center to a yshaft 111, which is held in the Velongatedbearing 112, inwhich it turns and which holds it in position. Thebearing is through the latters shaft 115, thepulley 116 thereon,

6 and the belt 117 which transmits motion from one pulley to the other.The motor 114 is held to the cross-slide 19 by the bracket 1118.

The transparent plastic enclosure 119 fixed to the carriage 4 by thelbracket 123, extends around the wheel 110 and the roll 7, to collectwater which drops onto the Wheel 110 from the nozzle 120, which entersthe enclosure 119. An outlet 121 is provided at the bottom of theenclosure 119, so that the water will run out of said enclosure, therebyavoiding accumulation of water there- At one end of the enclosure 119,there is an opening 1214 (shown dotted) through which the front of therollholding chuck 5 extends. At the other end, there is an opening 122through which bearing 112 and shaft 111 extend. This opening 122 must begreat enough transversely to the axis of roll 7 to permit the necessarytransverse motion of the bearing 112 which moves with they cross-slide19.

The water leaving enclosure 119 through outlet 121 drips through theopen space between the ways of the lathe 1,l into the drip pan 125, fromwhich it is carried by outlet 126 and hose 127 to the reservoir 128,from which it is pumped out by the pump 129 and reaches the nozzle 120through rubber hose 130. Y

The wheel 132, with the crank 131 forming part of it, can be used tomove the lathe carriage along the ways 2, 3 in the manner customary withlathes. The lever 133 locks the carriage in position, also in a mannerwellknown for lathes.

The cross-slide 19, as used herein, includes the number 134 slidable inslide 135 and the piece 136 slidable in the slide 137. Members 134, 135and 136 all move together along the main slide 137, and can beconsidered as a single piece in the present invention, although theycould be used separately in ordinary lathe practice.

The cutting Wheel 110 is preferably hollow ground.

What we claim is:

A machine for cutting wafer coils from a wound roll, said machinecomprising: means for holding said roll along a predetermined axis; acutting tool; means comprising a solenoid-actuated air cylinder foradvancing said cutting tool transversely against said roll for apredetermined distance to cut the same; means comprising an electricalswitch, actuated by the arrival of the cutting tool at the end of itsforward stroke, for actuating a l solenoidl to reverse the direction inwhich the air cylinder v moves the cutting tool to retractthe same; andmeans including an electrical switch actuated by arrival of the cuttingtool at the end of its retracting stroke for shifting said tool aVpredetermined distance in a direction' parallel to said predeterminedaxis, the direction in which this switch must be moved for actuationbeing opposite to vthe direction in which said first-mentioned switchmust be moved.

References Cited-inthe le of this patent .UNITED STATES PATENTS1,504,703 Nicholas Aug. 12, 1924 1,654,021 Thener Dec. 27, 1927v2,086,374 Wikle July 6, 1937 2,122,204' Gora June. 8, 1938 2,279,046Kearney f Apr. 7, 1942 2,369,617 Somerville ..*Feb. 131945 2,410,355Nesbitt Oct; 29, 1946 2,521,004 lGitter Sept. 5, 1950 2,557,308 'l YNippert Q-. .lune 19, 1951V `2,596,062. y Abbey Mayl 6, 1952 2,609,876Bauer'et al. Sept. 9, 1952k pjrhormey Apr'. 6, r1954

